Mercury??
(pig was shot in Morgan Hill, which is just south of San Jose)
There were mercury mines in the coastal mountains from Paso Robles north. Some were still active into the 1960’s.
Had a neighbor who worked in one in 1965.
Maybe mercury.
It does accumulate in fatty tissues.
Whether it would be blue, I don’t know.
I know copper and silver might make that color.
Silver in humans turns your skin blue.
Copper does similar.
Weird.